The present invention concerns in general terms motor vehicle headlights.
Headlights of the general type of the invention are described in the French patent No 96 12972 published under the number 2 755 210, and French patent application No 97 09210 published under the number 2 766 257, belonging to the Applicant.
This headlight comprises a real light source, means for concentrating the light radiation issuing from this source onto the end of a light pipe having a plurality of transparent blades juxtaposed in at least one direction, each transparent blade extending along the longitudinal axis of the light pipe and having, at least at its end furthest away from the real light source, an oblique reflection facet, the said facets constituting as many virtual light sources and being disposed so as to cooperate optically with interface elements with an axis parallel to the direction of illumination so that these project, in this direction, images corresponding to the facets.
Assembling the transparent blades of the light pipe of such a headlight is a tricky operation because of the number of blades to be assembled, the precise positioning of the reflection facets, and the fragility of the said blades produced preferentially from glass, this fragility relating particularly to their edges.
The present invention therefore proposes a novel headlight of the aforementioned type, in which a simple means of prior assembly of the blades together is provided so as to constitute a set of single-piece blades easy to manipulate in order to be mounted on a blade support.
According to the present invention there is provided a headlight for a motor vehicle, comprising a real light source, means for concentrating the light radiation issuing from this source onto the end of a light pipe consisting of a plurality of juxtaposed transparent blades in at least one direction, each transparent blade lying along the longitudinal axis of the said light pipe and having at least at its end furthest away from the real light source an oblique reflection facet, the said facets constituting as many virtual light sources and being disposed so as to cooperate optically with interface elements with their axis parallel to the direction of illumination so that they project, in this direction, images corresponding to the facets, wherein the transparent blades are bonded together at discrete points.
Preferably, each dot of glue has a diameter of between approximately 3 mm and approximately 5 mm.
According to a preferential embodiment of the headlight according to the invention, the transparent blades have different lengths, the shortest top transparent blade is bonded by a dot of glue to the bottom transparent blade, each intermediate transparent blade being bonded to another blade by two dots of glue situated at each end of the said blade.
The said transparent blades are produced from glass.
The glue used is advantageously a single-component glue which can be cross-linked under ultraviolet radiation, moisture or heat. It can be an epoxy glue or a silicone glue.
In addition, the present invention proposes a novel headlight of the aforementioned type, in which there is provided a system for mounting the light pipe providing good positioning of the facets, and of the light exit face of the latter vis-a-vis the interface elements so that the latter project, in the direction of illumination, images corresponding to the facets correctly positioned in the illumination beam, and good positioning of the entry face of the light pipe with respect to the light source, and in which there is provided a simple means of prior connection of the blades to each other so as to constitute a set of single-piece blades easy to manipulate in order to be mounted on a blade support.
More particularly, the headlight according to the invention has a reference piece for mounting the said light pipe, and at least one clamp able to grip the said juxtaposed transparent blades against the said reference piece in order to form a single-piece assembly.
Advantageously, the reference piece comprises a first generally flat horizontal part defining a horizontal reference plane, and a second generally flat vertical part, lying along the longitudinal axis of the light pipe and defining a vertical reference plane, and each clamp comprises a first internal surface opposite to the said first generally flat horizontal part, and a second internal surface opposite to the said second generally flat vertical part, the said first and second internal surfaces of each clamp having a protrusion exerting a thrust force on the juxtaposed transparent blades of the said light pipe in order to keep them in abutment against the first and second generally flat parts of the said reference piece, in a given position along the longitudinal axis of the said light pipe, so that their reflection facet or facets cooperate optically with the said interface elements so that the images of the facets projected by the said elements in the direction of illumination are positioned in a given manner.
Thus, advantageously according to the invention, the transparent blades constituting the light pipe are in abutment on two horizontal and vertical reference planes consisting of the first and second flat parts of the reference piece. The optical problems related to the manufacturing tolerances of the said blades are then dispensed with, the reflection facets of the said blades being positioned in a given manner with reference to the horizontal reference plane, and their light exit face being placed in a given manner with reference to the vertical plane.
Other advantageous and non-limitative characteristics of the headlight according to the invention are set out below.
The first flat horizontal part of the reference piece is a top part against which at least part of the top surface of the light pipe bears and the second flat vertical part of the reference piece is a front perforated part against which the front light exit faces of the transparent blades of the light pipe bear, and the first and second internal surfaces of each clamp are respectively a bottom horizontal surface coming into abutment against the bottom surface of the light pipe, and a rear vertical surface coming into abutment against the rear faces of the transparent blades.
Each clamp is a spring blade shaped like a U with a top leg positioned against the external face of the first flat horizontal part of the reference piece, and a bottom leg positioned against the bottom face of the light pipe.
The protrusions are formed with each clamp, or are attached to each clamp.
Each clamp is formed with the reference piece.
A compressible flexible element is provided between the light pipe and the first flat horizontal part of the reference piece. This flexible compressible element is a silicone shoe able to be compressed by approximately 20% of its thickness under the effect of the clamping of the reference piece and the said transparent blades in each clamp.
The first flat horizontal part of the reference piece has a flat high part and a flat low horizontal part, both horizontal, parallel and connected by a step, each clamp acting on the said flat low part and on the light pipe. The flat high horizontal part of the reference piece has an end edge aslant which carries a gauge for the positioning, on the horizontal axis of the light pipe, of the transparent blade directly in abutment against the flat high horizontal part of the said reference piece.
The transparent blades are bonded to each clamp and/or to the reference piece.
The reference piece is produced by moulding from aluminium. Each clamp is also advantageously produced by moulding from aluminium.